Sozo Break In

[boots]

It's true what they say about Sozo caps sounding better as they break in.

I just replaced the first two coupling caps in an AX84 HO with new Sozos. The ones I had in there were Mallory, I think (yellow with the IC logo - Mallory?).

I always thought that AX84 amp sounded too bright, so I thought I'd try some different caps.

I'm lucky enough to have scored a nice function generator (it was a "brother in law deal"). I have been letting the amp run 24 hours a day with some old tubes I don't care about. The sig gen is running a 10 second sweep from 20 Hz to 5 kHz. Since the amp has a master volume, I can keep the volume low while running the first two gain stages full out.

When I first installed the Sozos, they did indeed sound very bright.

After about 3 days of sweeping, the amp definitely seems to have more chunk in the bottom end. I am really starting to like the sound of this amp now.

I want to do the same treatment to my 5E3 clone, but it does not have a master volume. So I will need to come up with a silent dummy load. The sweeping is a very annoying thing to listen to.

So far this seems like the best, quickest way to break in tone caps.

[M Fowler]

IC= Illinois Caps

[ampgeek]

I always just pull the power tube(s) and let it rip!

Never had any issues doing it that way and it excercises the vast majority (if not all) of the caps of interest.

Cheers,
Dave O.

[Bob S]

A 200W 8 ohm dummy load resistor works for me.
24 hours is usually plenty IMHO.
I used to loan newly finished amps out.
Let someone else break them in.
Either way, it definitely takes the brittle edge off.

[dorrisant]

I usually just play it till it is broken in... but these are all greatto alternative ideas!

[Firestorm]

I wish someone with access to a decent lab (besides Sozo or any of the other boutique caps) would try to get to the actual physics of this. I know that I too often hear what I want to hear. Whenever I build a one-off amp for someone, I am certain that it sounds fantastic; but when I go to hear it played in public for the first time, I am usually terrified in case what I heard wasn't true.

[Firestorm]

I wish someone with access to a decent lab (besides Sozo or any of the other boutique caps) would try to get to the actual physics of this. I know that I too often hear what I want to hear. Whenever I build a one-off amp for someone, I am certain that it sounds fantastic; but when I go to hear it played in public for the first time, I am usually terrified in case what I heard wasn't true.

[boots]

I just terminated the break-in after about 80 hours. I think it's there. I noticed a definite improevement in the low end response and richness of the harmonics, especially in the lower registers. The amp sound delicious now - at least to me.

I would like to find a proper way to document the change. Like before and after scope shots. What would be the best waveform & frequency to illustrate what the cap is doing? It seems like you would have to look at something other than a sine wave to see what the cap is doing. Maybe the leading edge of a square wave, or a distorted, clipped sine wave?

I just started a burn-in on my 5E3 clone with the output tubes removed. I have a couple Musicaps in it that seem too bright and clean. Hopefully I will see the same kind of change I did with the Sozos after a few days.

Does anybody have any experience with Musicaps? They were very expensive, so I figured they must be good. But so far, they sound pretty sterile in a guitar amp.

[Structo]

In my limited experience, I find that the boutique capacitors that audiophiles drool over don't sound that great in a guitar amp.
Possibly because for the most part guitar amplifiers over the years used just about the cheapest components they could to boost the profit margin.

In fact most vintage amps used polyester (Mylar) and foil caps and polyester is pretty much considered old tech anymore.

I have used some of the expensive caps as tone caps in guitars however and I really like how the Hovland caps sounded in my strats.